EFFICACY OF NUTRITIONAL SUPPLEMENTS USED BY ATHLETES

Findings on the efficacy of nutritional supplements used by athletes a re reviewed. Many athletes have turned away from anabolic steroids and toward nutritional supplements in the hope of gaining a competitive e dge without threatening their health. Athletes may require slightly mo re protein than sedentary people do to maintain positive nitrogen bala nce, but it is dubious whether extra dietary protein will help someone to achieve athletic goals. Purified amino acids have become a popular if expensive form of protein supplementation; there is no scientific evidence, however, to support their use. Excessive protein supplementa tion can lead to dehydration, gout, liver and kidney damage, calcium l oss, and gastrointestinal effects. Supplementation with vitamins and m inerals in excess of recommended daily allowances appears to have no e ffect on muscle mass or athletic performance. Other substances touted as having ergogenic properties are carnitine, cobamamide, growth hormo ne releasers, octacosanol, and ginseng; again, there is no reliable sc ientific evidence to support claims that products containing these com pounds have ergogenic potential, and heavy supplementation may lead to adverse effects. Nutritional supplements are promoted through unsubst antiated claims by magazine advertisements, health food stores, coache s, and other sources. The FDA considers nutritional supplements to be foodstuffs, not drugs, and therefore has not required that they be pro ved safe and effective. Dosage guidelines are inadequate, and quality control is poor. The FDA has begun to revise regulations governing lab eling and health claims for these products. There is little if any evi dence that nutritional supplements have ergogenic effects in athletes consuming a balanced diet, and some products have the potential for ha rm.